Question: Why isn’t it preferred to name a Joker, “Joker” when discarding it?

Answer: From the “begin game” to before the “end game”, naming a Joker, “Joker” when discarding it, would naturally bring attention to it. To avoid doing this, it is acceptable to discard a Joker and name it “same”.  When naming a Joker “same,” if a player(s) are engrossed in their own hand and not watching the table, they might later notice a Joker in the center of the table and wonder who discarded it.    

Source:  Mah Jongg Made Easy 2024, page 24 #11